Planning studies for a new four-lane bridge to replace the existing Potomac River bridge are complete, the Maryland Transportation Authority has announced. There is, however, no money to build it, leaving the construction schedule unknown.

The last report needed, an environmental document, was approved by the Federal Highway Administration on Nov. 27, according to an MdTA announcement. But the project’s website warns: “Upon completion of the final environmental document in 2012, this project will become a candidate for MDTA capital improvement project funds. Currently, no funding is available for future phases, including final design, right-of-way and construction.”

This leaves the bridge in a sort of limbo, said MdTA spokesman Ray Feldmann.

“We’re finished with the planning phase, but the project now kind of moves into being a candidate for funds for design and construction. Because no funding has been identified for that, there is no construction schedule,” Feldmann said.

In 2010, MdTA decided to replace the existing two-lane Gov. Harry W. Nice Memorial Bridge, which links southern Charles County with King George, Va., with a four-lane span just to its north. The new bridge will include a shoulder for disabled vehicles and a path for pedestrians and bicyclists, both of which are lacking now.

The sidewalk and roadway will be separated by a barrier to protect walkers and bikers, Feldmann said.

The project will cost $850 million, MdTA estimates, but Charles County Commissioner Ken Robinson (D) thought the tab would likely reach $1 billion. He thought the project would stall without massive federal funding, which he said was justified because the bridge could serve as part of an escape route if Washington, D.C., residents ever had to evacuate during a catastrophe.

Robinson proposed changing the designation of the bridge, and of U.S. 301 from La Plata to King George, to an interstate, which would permit the federal government to pay for 90 percent of the bridge work.

“Unless the federal government decides to get involved, we’re going to be waiting for a really long time here,” he said.

He praised the new bridge’s sidewalk and hoped people would use it.

“They opened one up on the Wilson Bridge, and whenever I’m driving across, there are people on it. It wasn’t there before. I guess if you build it, they will come,” he said.